SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08cb31cc95e2bc94e0adddb2b1259bf579881bf604a0b050f303db7fd91944e7' 
  AND token = 'oTLBN073LizYoqF7n0I/Tetxk1zpJ7Sl53GIgEk+vKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}